This commit adds a new concept 'function' to do more text processing
in Kconfig.
A function call looks like this:
$(function,arg1,arg2,arg3,...)
This commit adds the basic infrastructure to expand functions.
Change the text expansion helpers to take arguments.
Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
---
Changes in v5:
- Drop delayed expansion of arguments.
Changes in v4:
- Error out if arguments more than FUNCTION_MAX_ARGS are passed
- Use a comma as a delimiter between the function name and the
first argument
- Check the number of arguments accepted by each function
- Support delayed expansion of arguments.
This will be needed to implement 'if' function
Changes in v3:
- Split base infrastructure and 'shell' function
into separate patches.
Changes in v2:
- Use 'shell' for getting stdout from the comment.
It was 'shell-stdout' in the previous version.
- Simplify the implementation since the expansion has been moved to
lexer.
scripts/kconfig/preprocess.c | 142 +++++++++++++++++++++++++++++++++++++++----
1 file changed, 130 insertions(+), 12 deletions(-)
diff --git a/scripts/kconfig/preprocess.c b/scripts/kconfig/preprocess.c
index a2eb2eb..f32a496 100644
--- a/scripts/kconfig/preprocess.c
+++ b/scripts/kconfig/preprocess.c
@@ -10,6 +10,10 @@
#include "list.h"
+#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
+
+static char *expand_string_with_args(const char *in, int argc, char *argv[]);
+
static void __attribute__((noreturn)) pperror(const char *format, ...)
{
va_list ap;
@@ -92,20 +96,123 @@ void env_write_dep(FILE *f, const char *autoconfig_name)
}
}
-static char *eval_clause(const char *str, size_t len)
+/*
+ * Built-in functions
+ */
+struct function {
+ const char *name;
+ unsigned int min_args;
+ unsigned int max_args;
+ char *(*func)(int argc, char *argv[]);
+};
+
+static const struct function function_table[] = {
+ /* Name MIN MAX Function */
+};
+
+#define FUNCTION_MAX_ARGS 16
+
+static char *function_expand(const char *name, int argc, char *argv[])
{
- char *tmp, *name, *res;
+ const struct function *f;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(function_table); i++) {
+ f = &function_table[i];
+ if (strcmp(f->name, name))
+ continue;
+
+ if (argc < f->min_args)
+ pperror("too few function arguments passed to '%s'",
+ name);
+
+ if (argc > f->max_args)
+ pperror("too many function arguments passed to '%s'",
+ name);
+
+ return f->func(argc, argv);
+ }
+
+ return NULL;
+}
+
+/*
+ * Evaluate a clause with arguments. argc/argv are arguments from the upper
+ * function call.
+ *
+ * Returned string must be freed when done
+ */
+static char *eval_clause(const char *str, size_t len, int argc, char *argv[])
+{
+ char *tmp, *name, *res, *prev, *p;
+ int new_argc = 0;
+ char *new_argv[FUNCTION_MAX_ARGS];
+ int nest = 0;
+ int i;
tmp = xstrndup(str, len);
- name = expand_string(tmp);
+ prev = p = tmp;
+
+ /*
+ * Split into tokens
+ * The function name and arguments are separated by a comma.
+ * For example, if the function call is like this:
+ * $(foo,$(x),$(y))
+ *
+ * The input string for this helper should be:
+ * foo,$(x),$(y)
+ *
+ * and split into:
+ * new_argv[0] = 'foo'
+ * new_argv[1] = '$(x)'
+ * new_argv[2] = '$(y)'
+ */
+ while (*p) {
+ if (nest == 0 && *p == ',') {
+ *p = 0;
+ if (new_argc >= FUNCTION_MAX_ARGS)
+ pperror("too many function arguments");
+ new_argv[new_argc++] = prev;
+ prev = p + 1;
+ } else if (*p == '(') {
+ nest++;
+ } else if (*p == ')') {
+ nest--;
+ }
- res = env_expand(name);
+ p++;
+ }
+ new_argv[new_argc++] = prev;
+
+ /*
+ * Shift arguments
+ * new_argv[0] represents a function name or a variable name. Put it
+ * into 'name', then shift the rest of the arguments. This simplifies
+ * 'const' handling.
+ */
+ name = expand_string_with_args(new_argv[0], argc, argv);
+ new_argc--;
+ for (i = 0; i < new_argc; i++)
+ new_argv[i] = expand_string_with_args(new_argv[i + 1],
+ argc, argv);
+
+ /* Look for built-in functions */
+ res = function_expand(name, new_argc, new_argv);
if (res)
goto free;
+ /* Last, try environment variable */
+ if (new_argc == 0) {
+ res = env_expand(name);
+ if (res)
+ goto free;
+ }
+
res = xstrdup("");
free:
+ for (i = 0; i < new_argc; i++)
+ free(new_argv[i]);
free(name);
free(tmp);
@@ -124,14 +231,14 @@ static char *eval_clause(const char *str, size_t len)
* after the corresponding closing parenthesis, in this case, *str will be
* $(BAR)
*/
-char *expand_dollar(const char **str)
+static char *expand_dollar_with_args(const char **str, int argc, char *argv[])
{
const char *p = *str;
const char *q;
int nest = 0;
/*
- * In Kconfig, variable references always start with "$(".
+ * In Kconfig, variable/function references always start with "$(".
* Neither single-letter variables as in $A nor curly braces as in ${CC}
* are supported. '$' not followed by '(' loses its special meaning.
*/
@@ -158,10 +265,16 @@ char *expand_dollar(const char **str)
/* Advance 'str' to after the expanded initial portion of the string */
*str = q + 1;
- return eval_clause(p, q - p);
+ return eval_clause(p, q - p, argc, argv);
+}
+
+char *expand_dollar(const char **str)
+{
+ return expand_dollar_with_args(str, 0, NULL);
}
-static char *__expand_string(const char **str, bool (*is_end)(char c))
+static char *__expand_string(const char **str, bool (*is_end)(char c),
+ int argc, char *argv[])
{
const char *in, *p;
char *expansion, *out;
@@ -177,7 +290,7 @@ static char *__expand_string(const char **str, bool (*is_end)(char c))
if (*p == '$') {
in_len = p - in;
p++;
- expansion = expand_dollar(&p);
+ expansion = expand_dollar_with_args(&p, argc, argv);
out_len += in_len + strlen(expansion);
out = xrealloc(out, out_len);
strncat(out, in, in_len);
@@ -210,13 +323,18 @@ static bool is_end_of_str(char c)
}
/*
- * Expand variables in the given string. Undefined variables
+ * Expand variables and functions in the given string. Undefined variables
* expand to an empty string.
* The returned string must be freed when done.
*/
+static char *expand_string_with_args(const char *in, int argc, char *argv[])
+{
+ return __expand_string(&in, is_end_of_str, argc, argv);
+}
+
char *expand_string(const char *in)
{
- return __expand_string(&in, is_end_of_str);
+ return expand_string_with_args(in, 0, NULL);
}
static bool is_end_of_token(char c)
@@ -234,5 +352,5 @@ static bool is_end_of_token(char c)
*/
char *expand_one_token(const char **str)
{
- return __expand_string(str, is_end_of_token);
+ return __expand_string(str, is_end_of_token, 0, NULL);
}
--
2.7.4
--
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